                (a) Field of the Invention        
The present invention relates to a liquid crystal display, and particularly to a vertically aligned liquid crystal display having a pixel area divided into a plurality of small domains for wide viewing angle.
(b) Description of Related Art
In general, a liquid crystal display (referred to as an “LCD” hereinafter) has an upper panel, a lower panel and a liquid crystal layer disposed therebetween. The upper panel has a common electrode, a plurality of color filters and the like, and the lower panel has a plurality of thin film transistors, a plurality of pixel electrodes connected thereto and so on. In addition, a pair of polarizers are attached to the panels. The pixel electrodes and the common electrode are applied with electrical voltages to generate electric field which varies the orientation of liquid crystal molecules. The variation of the orientation of the liquid crystal molecules changes the polarization of light incident on the liquid crystal layer after passing through one of the polarizers, thereby controlling the transmittance of the light out of the other polarizer.
One drawback of a conventional LCD is its narrow viewing angle. Several methods for widening the viewing angle have been developed. One of the methods is to align the long axes of the liquid crystal molecules vertical to the panels and to form apertures or protrusions in the pixel electrodes and/or in the common electrode facing the pixel electrodes. The domain defining members such as aperture or protrusions define domains, and the domains in turn define the alignment of the liquid crystal molecules therein.
The apertures formed in the pixel electrodes and the common electrode result in a fringe field. By using the fringe field, the tilt directions of the liquid crystal molecules are controlled to enlarge the viewing angle.
The protrusions are provided on the pixel electrodes and the common electrode formed in the upper and the lower panels. The electric field altered by the protrusions are used to control the tilt directions of the liquid crystal molecules.
Another method is by forming apertures in the pixel electrodes of the lower panel, while having protrusions on the common electrode of the upper panel. The tilt directions of the liquid crystal molecules are controlled to form domains by using the fringe field generated by the apertures and the protrusions.
In addition, gate lines and data lines provided in the lower panel and arranged in rows and columns carry scanning signals and image signals, and the pixel electrodes and the thin film transistors are disposed in rectangular areas defined by the intersections of the gate lines and the data lines. When the scanning signals and the image signals are transmitted by the gate lines and the data lines the signals influence the electric fields adjacent thereto, and the stability of the domains and the image quality deteriorate.